Industrial robots are programmed to perform specific technological actions with high precision. These actions are determined by programmed routines that specify the direction, acceleration, velocity, deceleration, and distance pertaining to a series of coordinated motions of industrial robots. Further, the industrial robots are increasingly being used to reduce human labor and manually induced error by automating industrial manufacturing processes.
Generally, industrial robots in the form of robotic arms are used in a variety of applications such as welding, painting, assembly, palletizing, spraying, cutting, and material handling. Usage of robotic arms in such applications increases the speed and accuracy of the job. Typically, the robotic arm or industrial robot is provided with 3 to 9 axis of movement having its wrist adapted to hold a tool for operations such as precision metal cutting, welding and the like. Further, the robotic arms are gantry mounted or floor mounted and movement of a robotic arm is restrained to “Maximum Reach” of the robotic arm, wherein the “Maximum Reach” of the robotic arm is defined by point of mounting of the robotic arm, architecture, and dimensions of the robotic arm. Accordingly, the tool held in a wrist of a robotic arm faces constraint of limited reach and sometimes fails to reach certain areas of a work-piece that are to be worked upon by the tool.
FIG. 1 of the accompanying drawings illustrates a prior-art schematic arrangement 100 of a gantry 50 mounted inverted robotic arm 10 adapted to carry out operations on a rectangular work-piece 20. The arrangement 100 includes a bed 30 supporting the rectangular work-piece 20. The bed 30 is further supported by a plurality of supporting legs 40. The robotic arm 10 is adapted to hold a tool 60 that is adapted to perform operations on the rectangular work-piece 20. The tool 60 can be a plasma cutting torch, a welding torch or any other operation specific tool. Referring to FIG. 1, the robotic arm 10 includes a plurality of elements coupled to each other at its ends for rotating with respect to each other to enhance flexibility and reach of the robotic arm 10. Further, the gantry 50 is also adapted to slide in a restrictive access position including horizontal, parallel or alternatively perpendicular configuration with respect to the bed 30 to facilitate movement of the robotic arm 10 along a length or width of bed 30.
The tool 60 is secured to a wrist of the robotic arm 10, whereby the tool 60 faces a constraint of limited reach that further shortens when the tool 60 is required to operate on bottom face 70 and proximate areas. Further, the reach of the tool 60 held in the wrist of the robotic arm 10 (both floor mounted and gantry mounted) diminishes when operating on the bottom face 70 of the rectangular work-piece 20 as the work-piece material obstructs movement of the robotic arm 10. The reach of the tool 60 held in the wrist of the robotic arm 10 is reduced by varying amounts based on the dimensions of the setup 100, when the tool 60 is operating on the bottom face 70 of the work-piece 20 as compared to when the tool 60 is operating on the top face 80 or side faces of the rectangular work-piece 20. Inability of the tool 60 to work on regions on bottom face 70 of the rectangular work-piece 20 due to inaccessibility of the bottom face 70 causes inoperability on bottom surface 70. Further, movement of the robotic arm 10 in stringent accessible zones defined by “Maximum Reach”, architecture and dimensions of the robotic arm 10 may cause damage to the robotic arm 10 due to increase in chances of robotic arm striking the work-piece while reaching out to a faraway zone on the work-piece.
In spite of the above mentioned problems, machining operations or any other operations may be performed on both the top face 80 and the bottom face 70 of the rectangular work-piece 20 as per following steps. In a first step, machining operations are performed on the top face 80 of the rectangular work-piece 20 followed by turning the rectangular work-piece 20 upside down such that the earlier bottom face 70 of the work-piece becomes the top face to facilitate machining of the bottom face 70 as well. In a second step, after turning the rectangular work-piece 20 upside down, the machining operations may now be performed on the top face (bottom face 70 before turning the rectangular work-piece 20 upside down). Thus, machining operations may be performed on both the top face 80 and bottom face 70 of the rectangular work-piece 20 as the tool 60 is adapted to freely and conveniently operate on the top face of the work-piece without any constraint of reach.
However, turning the rectangular work-piece 20 upside down requires manual intervention, which is a difficult task, especially when the rectangular work-piece 20 is heavy and is of large dimensions. Furthermore, turning the rectangular work-piece 20 upside down considerably increases cycle time of the machining operation and can lead to damage of the work piece or the tool held in the wrist of the robotic arm. In some cases, for example welding or plasma cutting operations, temperature of the work piece drastically increases and the work piece cannot be touched for some time immediately after operation thereon, thus, the work piece must be turned around for operations on the other side only after waiting for some time. In other cases, such as painting, the operated surface cannot be touched until drying, thereby requires the operation to be held until the operated surface is dry. Accordingly, turning of the work piece to carry out operations on both surfaces thereof is a tedious task and may adversely affect the cycle time of the operation.
Further, turning the work piece can also be a problem as most beds are not designed to perform such operations, and forcefully turning the work-piece leads to loss of alignment of the bed with respect to the robot or the gantry; and could also damage the bed or the work piece itself.
Thus, a need is felt to enhance reach of the high speed tool 60 on the bottom face 70 of the work piece without turning the rectangular work-piece 20 upside down, thus, decreasing the cycle time of the machining operation and ensuring safety.